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authorEric Dumazet <edumazet@google.com>2024-04-18 09:32:41 +0200
committerDavid S. Miller <davem@davemloft.net>2024-04-19 12:34:07 +0200
commitc5f1dde7f731e7bf2e7c169ca42cb4989fc2f8b9 (patch)
tree0a57c5f00f4792365f4fa386a35f27aec6f0d41a
parentnet_sched: sch_tfs: implement lockless etf_dump() (diff)
downloadlinux-c5f1dde7f731e7bf2e7c169ca42cb4989fc2f8b9.tar.xz
linux-c5f1dde7f731e7bf2e7c169ca42cb4989fc2f8b9.zip
net_sched: sch_ets: implement lockless ets_dump()
Instead of relying on RTNL, ets_dump() can use READ_ONCE() annotations, paired with WRITE_ONCE() ones in ets_change(). Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/sched/sch_ets.c25
1 files changed, 14 insertions, 11 deletions
diff --git a/net/sched/sch_ets.c b/net/sched/sch_ets.c
index 835b4460b448..f80bc05d4c5a 100644
--- a/net/sched/sch_ets.c
+++ b/net/sched/sch_ets.c
@@ -646,7 +646,7 @@ static int ets_qdisc_change(struct Qdisc *sch, struct nlattr *opt,
sch_tree_lock(sch);
- q->nbands = nbands;
+ WRITE_ONCE(q->nbands, nbands);
for (i = nstrict; i < q->nstrict; i++) {
if (q->classes[i].qdisc->q.qlen) {
list_add_tail(&q->classes[i].alist, &q->active);
@@ -658,11 +658,11 @@ static int ets_qdisc_change(struct Qdisc *sch, struct nlattr *opt,
list_del(&q->classes[i].alist);
qdisc_tree_flush_backlog(q->classes[i].qdisc);
}
- q->nstrict = nstrict;
+ WRITE_ONCE(q->nstrict, nstrict);
memcpy(q->prio2band, priomap, sizeof(priomap));
for (i = 0; i < q->nbands; i++)
- q->classes[i].quantum = quanta[i];
+ WRITE_ONCE(q->classes[i].quantum, quanta[i]);
for (i = oldbands; i < q->nbands; i++) {
q->classes[i].qdisc = queues[i];
@@ -676,7 +676,7 @@ static int ets_qdisc_change(struct Qdisc *sch, struct nlattr *opt,
for (i = q->nbands; i < oldbands; i++) {
qdisc_put(q->classes[i].qdisc);
q->classes[i].qdisc = NULL;
- q->classes[i].quantum = 0;
+ WRITE_ONCE(q->classes[i].quantum, 0);
q->classes[i].deficit = 0;
gnet_stats_basic_sync_init(&q->classes[i].bstats);
memset(&q->classes[i].qstats, 0, sizeof(q->classes[i].qstats));
@@ -733,6 +733,7 @@ static int ets_qdisc_dump(struct Qdisc *sch, struct sk_buff *skb)
struct ets_sched *q = qdisc_priv(sch);
struct nlattr *opts;
struct nlattr *nest;
+ u8 nbands, nstrict;
int band;
int prio;
int err;
@@ -745,21 +746,22 @@ static int ets_qdisc_dump(struct Qdisc *sch, struct sk_buff *skb)
if (!opts)
goto nla_err;
- if (nla_put_u8(skb, TCA_ETS_NBANDS, q->nbands))
+ nbands = READ_ONCE(q->nbands);
+ if (nla_put_u8(skb, TCA_ETS_NBANDS, nbands))
goto nla_err;
- if (q->nstrict &&
- nla_put_u8(skb, TCA_ETS_NSTRICT, q->nstrict))
+ nstrict = READ_ONCE(q->nstrict);
+ if (nstrict && nla_put_u8(skb, TCA_ETS_NSTRICT, nstrict))
goto nla_err;
- if (q->nbands > q->nstrict) {
+ if (nbands > nstrict) {
nest = nla_nest_start(skb, TCA_ETS_QUANTA);
if (!nest)
goto nla_err;
- for (band = q->nstrict; band < q->nbands; band++) {
+ for (band = nstrict; band < nbands; band++) {
if (nla_put_u32(skb, TCA_ETS_QUANTA_BAND,
- q->classes[band].quantum))
+ READ_ONCE(q->classes[band].quantum)))
goto nla_err;
}
@@ -771,7 +773,8 @@ static int ets_qdisc_dump(struct Qdisc *sch, struct sk_buff *skb)
goto nla_err;
for (prio = 0; prio <= TC_PRIO_MAX; prio++) {
- if (nla_put_u8(skb, TCA_ETS_PRIOMAP_BAND, q->prio2band[prio]))
+ if (nla_put_u8(skb, TCA_ETS_PRIOMAP_BAND,
+ READ_ONCE(q->prio2band[prio])))
goto nla_err;
}